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Analysis Model and Displacement Measurement Prof. Ho-Kyung Kim (Seoul Nat’l Univ.) Prof. HaeSung Lee (Seoul Nat’l Univ.) Prof. Nam-Sik Kim (Pusan Nat’l.

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Presentation on theme: "Analysis Model and Displacement Measurement Prof. Ho-Kyung Kim (Seoul Nat’l Univ.) Prof. HaeSung Lee (Seoul Nat’l Univ.) Prof. Nam-Sik Kim (Pusan Nat’l."— Presentation transcript:

1 Analysis Model and Displacement Measurement Prof. Ho-Kyung Kim (Seoul Nat’l Univ.) Prof. HaeSung Lee (Seoul Nat’l Univ.) Prof. Nam-Sik Kim (Pusan Nat’l Univ.)

2 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Korean group  Analysis model and displacement measurement Seoul National University (SNU)  Visual inspection and condition assessment PEC (Pyunghwa Engineering Consultants) KCQR (Korea Construction Quality Research Center) Inha Univ.  Model updating for the SMART load rating KEC (Korea Expressway Corporation) Sejong Univ.  Application of NDT techniques for online monitoring KAIST  4 universities and 3 companies

3 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Target span  Southbound of Span 2 Severe vibrations have been observed. The longest span length Deteriorations on bearings, bracings and cracks on pier cap Controlled loading test data is available (tested by Drexel Univ.)

4 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University FEA Software  MIDAS Civil 2006 Database including live load models in the design specification of Korea, U.S., etc. Sectional properties of structural members (such as bracing, diaphragm) are easily obtained using in-built database.

5 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University FE modeling  RC Slab : * solid element  Girder Web & flange : ** plate element Plate element for web Plate element for flange * 8 node 3D solid element (Isometric formulation with incompatible modes) ** 3 or 4 node 3D plate element (Kirchhoff Plate Theory)

6 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University FE modeling  Bracing, diaphragm : 2 node space frame elements Diaphragm Bracing

7 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University FE modeling  Variation of flange thickness Top flange with two thicknesses Bottom flange with three different thicknesses Sectional properties are varied according to flange details

8 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Boundary conditions  Fixed bearing Between girders and pier 1 Rotation in y direction is released  Movable bearing Between girders and pier 2 Rotation in y direction, translation in x direction are released P1W P2W xy Movable bearings Fixed bearings

9 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University 3D full modeling

10 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Measurement of displacement 1.Direct measuring with LVDT 2.Reconstruction from ACCELEROMETER 3.Identification from images of CAMCORDER

11 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Reconstruction of displacement from measured acceleration  Variational Statement for the Minimization Problem  Integration by Parts Twice  Governing Equation and Boundary Conditions The same governing equation for a beam on elastic foundation Discretization of governing equation yields FFIR type filter for reconstruction

12 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University  Measured Displacement The static displacements are included in measured displacements. To eliminate the static components from the measurements, a moving average technique is employed. Dynamic displacement

13 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University  Results Reconstructed displacements LVDTACC Reconstruction

14 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Displacement from camcorder images  Digital Image Processing Algorithm Image Arrangement Grid Generation(Target Image) Sum Table Calculation Sub-pixel Estimation Displacement Response Correlation Size Selection(ROI) NCC Computation Target Initial coordinate (x 1,y 1 ) Frame1(t 0 ) ROI Coordinates of best match(x 3,y 3 ) Frame3(t 2 ) Target ROI Coordinates of best match(x 2,y 2 ) Frame2(t 1 ) Target ROI Enhancing the resolution of displacement responses by using the 2 nd Order Polynomial Transform Function Searching for the position where the maximum value of Normalized Cross Correlation Coefficient is obtained

15 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University  Measurement conditions Target(L/2) Span-2 Target Span Camera Image Target (L/2) Target (2L/3) Span-2 Target Camcorder SAMSUNG VM HMX10A Sampling Rate LVDT : 100Hz Camcorder : 60fps Resolution 1280 x 720 pixels (Full High Definition) 50mm/101pixel s= 0.495mm/pixel Identification of displacement from camcorder images

16 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University  Comparison of Responses on LVDT Identified displacements Vertical

17 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Time plan and future test-bed in Korea Field testingJune 6~10, 2011 Preliminary reportJuly 15, 2011 Final reportJuly 30, 2011  Time plan  Future test-bed in Korea  A new KEC project for evaluating the load carrying capacity of bridges will start from July 2011 to December  Reliability-based approaches will be examined.  A typical concrete bridge and a steel bridge will be selected and tested in 2012 and  The bridges will be open for testing to international society.  Typical sensors will be installed by Korean side.

18 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Time plan and future test-bed in Korea  Equations for Load Rating  AASHTO LRFR  CHBDC RC-T Beam PSC Beam Live Load Capacity Factor Mean Load Method

19 IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Korean group and IBS supporters Many thanks to Jeff and Prof. Aktan for their sincere assistance.


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